And Then There Were None — Agatha Christie (1939)

Agatha Christie's masterpiece is the best-selling mystery novel of all time with over 100 million copies sold. Ten people are invited to an island under false pretences and begin dying one by one in accordance with a children's rhyme. Its solution is so perfectly constructed that, 85 years after publication, it still surprises readers who encounter it fresh. Christie's locked-room plotting has never been bettered.